<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div {
      width: 100px;
      height: 100px;
      background-color: pink; 
      border-radius: 50%;
      background-image: radial-gradient(
        30px at 50px 50px,
        red,
        pink
      );
    }

    button {
      width: 100px;
      height: 40px;
      background-color: green;
      border: 0;
      border-radius: 5px;
      color: #fff;
      background-image: radial-gradient(
        30px at 30px 20px,
        rgba(255,255,255,0.2),
        transparent
      );
      
    }
  </style>
</head>
<body>
  <div></div>
  <button>按钮</button>
</body>
</html>